How Much Does An ADU Cost?

In the Bay Area, the high cost of living and the lack of affordable housing are two of the most significant challenges many regional residents face. Accessory dwelling units can simultaneously solve these problems, making them increasingly popular throughout the area. Homeowners can benefit from the additional potential rental income they may earn, while renters may find living in an ADU to be more affordable and accessible than traditional rental units.

ADUs are the perfect option for those looking for extra space to house an extended, multigenerational family. Offering proximity to loved ones while maintaining a separate living space, ADUs can also give seniors the care they need in a family setting while they age.

With imaginative designs and innovative solutions, Valley Home Builders’ options can accommodate the wants and needs of homeowners in San José and the Bay Area. Read on to learn how to build an ADU in California, including building cost considerations, sizing, permitting requirements and more.

What Is an ADU?

In recent years, the interest in and desire for ADUs has risen significantly throughout California. An accessory dwelling unit is an additional home constructed on the same parcel of land as the original structure. ADUs can come in various sizes, styles and constructions. Often, they can co-exist on the same land as a single-family home, an apartment building, condos or other residential buildings.

What size are ADUs? A tiny home is a type of ADU, and garage spaces converted into living areas can also be ADUs. The skyrocketing demand for ADUs in California has led state legislators to relax many previous codes and restrictions surrounding who can build an ADU and where its location can be. Depending on where you live, guidelines may dictate your ADU’s exact specifications. However, provided you obtain the appropriate ADU permits, local governments cannot prevent you from constructing one.

When building an ADU, you can choose from three types

• Attached ADU: These are additional living spaces within your house. Attached ADUs are add-ons that function as apartments or townhomes, often with separate entry points from the rest of the home.
• Detached ADU: These stand-alone structures are independent from the main dwelling. Cottages are a common form of detached ADUs.
• Conversion: Conversion units are another popular form of ADUs. Often, conversion-style ADUs are former garages or other existing structures transformed into living spaces by adding amenities like plumbing and HVAC. With this type of ADU, the homeowner should be aware that the conversion space will have to meet all existing building codes and safety permits, as would any new building project.

Many homeowners may be interested in using their ADU as a rental property for the potential to earn additional rental income. Others might wish to use theirs as an in-law suite, office space or home yoga studio. In some cases, people will use ADUs for a multigenerational family and to house and care for older parents. ADUs’ multiple benefits have made them sought-after, especially in the South Bay Area.

How Much Does It Cost to Build an ADU?

An ADU’s cost can vary widely, depending on factors like its size, materials used, construction type, finishes and other features like site conditions. For example, having to level steeply sloped land will significantly impact the overall price. Given all these variables, it’s nearly impossible to provide an exact cost for an ADU; However, based on the large number of ADUs built by Valley Home Builders, the average cost can be anywhere between $300-600 a square foot for a move-in ready ADU.

When considering the financial commitment required to build an ADU, first consider what construction type you want for your project and how large you want your ADU to be. Attached ADUs, detached ADUs and conversion projects will each require different levels of financial investment. Of course, the size and finishes used will also impact the overall cost. Consulting directly with a contracting team that provides professional ADU services is the best way to get an accurate quote for your project.

Design

The design costs for an ADU project may vary significantly depending on the unit type. If you’re starting from scratch, prices will typically be higher, since you will need to pay for the materials to start the project. Attached ADUs and conversions requiring fewer materials may cost less, whereas detached ADUs will require an entirely new structure. Your desired customizations will also impact price. For example, if you want a vaulted ceiling instead of a flat one, you can expect to pay a bit more.

Permit

Luckily, California state laws protect homeowners’ rights to build ADUs. However, these construction projects must still adhere to building codes. Research any necessary ADU permit costs in your city and factor them into your ADU project’s budget.

Construction

Like design costs, an ADU’s construction costs may vary widely, depending on each project’s specific scope. Prices are constantly fluctuating, so you’ll want to contact your contractor for a more accurate estimate. An ADU’s complexity, design elements and finishes can significantly influence the overall cost — particularly in California, with our state’s consistently high costs of living.

Labor

Costs will also vary depending on how much labor you’ll need — the design and degree of difficulty will demand more or less depending on the situation. Finding the right service is essential so you can trust the labor you’re paying for. Valley Home Builders offers transparency throughout the entire process and promises to do quality work.

Furnishing and Landscaping

Of course, constructing a living space alone is not enough to make the space livable. That will also require furniture, appliances, housewares and, in some cases, landscaping. These costs can add up quickly, so don’t overlook them when figuring out your ADU’s budget. When you work with Valley Home Builders, we also factor extras like move-in-ready finishes and appliances into our proposals.

How Long Does It Take to Build ADUs?

The amount of time it will take to build an ADU will depend on the type and size of the structure in question.

The process for building an on-site, new-construction ADU includes various steps. First, you must have your architectural plans approved by your municipality to obtain the appropriate permits. Once you’ve acquired all needed permits and approvals, the construction process can begin in earnest. The building process might seem challenging to some, but your finished ADU will offer a multitude of benefits.

An average timeframe is three to six months. Valley Home Builders has an in-house foundation and framing team to provide shorter turnaround times.

In some cases, a garage/basement conversion is the quickest type of ADU to complete. Because the conversion will take place in an existing structure, you’ll likely have most of the materials you need already, offering a quick and cost-effective project. Depending on the original state of your garage, basement or other conversion space, hookups to HVAC, plumbing and electrical may already be in place — another boon to your construction timeline.

Accessory Dwelling Unit FAQs

How Big Are ADUs From Valley Home Builders?

There is no definitive answer to this question! The size of an ADU from Valley Home Builders can vary, depending on your lot size, needs and wants. For local agencies without an ordinance, an ADU cannot exceed 1,200 square feet, and attached ADUs cannot exceed 50% of the primary dwelling’s size. A junior accessory dwelling unit must be 500 square feet or fewer — in most cases, these properties are legal for owner-occupancy only. Specifications may vary, depending on your property, different laws where you live and how you plan to use your ADU.

Though city ordinances might make it more challenging to build an ADU, state law will always override those. California continues to push legislation that eases ADU construction restrictions.

How Much Does an ADU Cost in California?

Numerous factors can affect an ADU’s total price tag, including the type you choose to build, its square footage, your site conditions and various labor and permitting costs. Of course, when you build a high-quality, well-appointed ADU with desirable amenities, you may command a higher rental income. We’ve created our ADU estimator tool to give you an estimate of what you can expect to pay for building an ADU in the South Bay Area.

When you work with Valley Home Builders, you can feel confident in the financial investment you are making in your ADU. In support of our peerless service and excellence in design and construction, we’ll include a one-year craftsmanship guarantee in your building project’s contract.

How Much Rental Income Can I Earn From an ADU?

The amount of income you can expect to earn from your ADU will vary depending on the unit’s size, appliances, design features and comparable properties in your neighborhood. For example, a two-bedroom unit will typically have higher rental potential than a one-bedroom or studio flat. Investing in the highest-quality construction methods, designer finishes and appliances will cost more upfront, but can have significantly higher ROI than less expensive finishes. Renters are typically willing to pay more for well-designed spaces that offer amenities like dishwashers and washer/dryer combos.

Can I Customize an ADU From Valley Home Builders?

Yes! We specialize in creative designs and innovative solutions for all your construction needs, including ADUs. With over 15 years of experience, Valley Home Builders has established ourselves as leading ADU professionals in the South Bay Area.

Some typical concerns clients ask us to solve with their ADU include:

• Expanding their cramped living space
• Providing safety and the opportunity to check in on elderly family members
• Privacy for and from potential renters
• Entertainment needs, like an outdoor kitchen or home fitness studio

At Valley Home Builders, we provide garage conversions, attached and detached ADUs. In collaboration with our contracting and design teams, homeowners can create an ADU space that is ideal for them, their property and their families.

What Are the Benefits of an ADU From Valley Home Builders?

Homeowners can expect to gain numerous advantages from an ADU built by Valley Home Builders. Some of the most impactful include creating a flexible living space, improved infrastructure, comfortable multigenerational living, additional rental income and increased property value.

While most contractors focus on price, Valley Home Builders’ top priority will always be the client. We provide the highest possible customer service and value. Instead of selling products, we offer solutions to our customers’ problems. Satisfied clients have benefited significantly from the honesty, transparency and unmatched customer experience we provide.

Valley Home Builders offers a convenient portal you can access with a unique username and password so you can monitor progress at any moment. You can speak with your project manager, check schedules and view photos and payment plans, all online. It’s a transparent process that gives you access whenever you want it.

What Areas Does Valley Home Builders Serve?

At Valley Home Builders, we are the premier leaders in ADU construction, new home builds, additions and home remodeling throughout the Bay Area. In particular, we have worked extensively in Santa Clara and San Mateo counties. Our expertise allows us to cut through the red tape and obtain all necessary permits and inspections quickly and affordably.

Contact Valley Home Builders to Learn More About Our ADU Services

At Valley Home Builders, we are ready to help you turn your dream ADU into a reality. From design plans to construction work to selecting finishes, our skilled contracting and design teams offer world-class customer service and value to each of our clients.

Valley Home Builders is your one-stop shop for ADUs. We offer comprehensive services that guide you through the process from start to finish. Our in-house team will work with you to solve all of your space needs, providing you with expert help in design, architecture, engineering, permit handling and construction. You’ll receive quality customer service the whole way through — right up until we hand you the keys to your new ADU.

Request your complimentary consultation today, and our team will be in touch with you as soon as possible. Thank you for trusting us with all your home design projects. Whether you plan to build an ADU, add on to your home or remodel your kitchen and bathroom, Valley Home Builders can provide you with benefits you’ll enjoy for years to come.